''But it is low growth and the sharemarket is doing better than the economy because the listed companies are doing better than the economy.''

Economists say one of the reasons for that is almost half the sales of US companies come from offshore. That allows US-listed companies to benefit from the rise of consumers in developing countries, not only developing Asian countries but also countries such as Brazil.

It should not be forgotten that America is still the world's great innovator, Sherwood says. ''Just look at sales of the iPad.'' But it is not only in technology - particularly information technology with companies such as Apple, Google and Facebook - that America leads.

The chief economist at AMP, Shane Oliver, points out that the relatively low US dollar has helped to increase the competitiveness of US industry and that a greater share of its exports is going to Asia and contributing to the performance of US shares.

But something else is happening in America that Oliver believes is likely to be a ''game changer'', and that is access to domestic supplies of cheap energy.

Energy self-sufficiency

Many countries have huge deposits of shale gas and oil, but America is the best at exploiting it.

Fracking technology and horizontal drilling are being used to extract otherwise inaccessible deposits of shale gas and oil. Oliver says those deposits will likely be a ''massive benefit'' to the US. ''[America] will, in a few years' time, likely be energy self-sufficient,'' he says.

The chief executive and co-founder of special international shares fund manager Platinum Asset Management, Kerr Neilson, says the exploitation of cheap shale gas in the US is an industry that has to grow, despite slow global growth.

Platinum's portfolios have exposures to the oil and gas sector, not only in America but also in countries such as Canada with Nexen and the Netherlands through Royal Dutch Shell.

America's older companies still feature strongly in the global share portfolios of most fund managers. Platinum's flagship International Fund, for example, includes Microsoft and Bank of America among its top 10 holdings.

The founder of global shares fund manager Peters MacGregor Capital Management, Wayne Peters, says his Global Fund has holdings in Bank of America and another of America's largest banks, Wells Fargo. He says Bank of America's shares are trading at less than half their book value and management is ''righting the ship''.

A co-founder of global shares fund manager Morphic Asset Management, Chad Slater, also finds good opportunities in the US.

''The US is one of the world's most flexible economies and that is being shown once again,'' he says. ''It is one of the best countries in the world at penetrating overseas markets.''

European shares are cheap but there are still too many risks, he says, and China's economic growth is slowing. Slater has about 30 per cent of his Global Opportunities Fund invested in US-listed shares, which are the fund's biggest exposure. He is invested in Valero Energy, which has refineries and ethanal plants in the US, Canada, Britain and Caribbean. Valero produces fuels from less-expensive, heavy, ''sour'' crude oil.

Real estate

Another theme favoured by fund managers is US real estate. Slater says there is an under-supply of new houses in places where people want to live and an oversupply of established houses in less-desirable locations. The US has regional markets for home builders.

His fund holds shares in five building companies in different regions to cover the risk.

''There is not much inventory there if you want a new house,'' Slater says. ''These guys [home builders] have been so scarred that they have no interest in overbuilding and are building to demand.''

Peters says the Global Fund is skewed to US shares because good opportunities are there, although the fund manager remains cautious overall, with more than 30 per cent of the fund in cash. The fund has a holding in the US-listed Howard Hughes Corporation, which is a developer and operator of ''master-planned communities'' and ''mixed-use'' properties.

Peters says the investment is a ''play on the US real estate market that is at, or around, the bottom''.

He anticipates the oversupply of housing will disappear within the next five years.

Manufacturers return to the US

Manufacturing in the US has been in trouble for a long time, with much of it moving offshore to where labour is cheaper, such as China, and because of falling domestic demand for products, such as cars.

Before the global financial crisis, Americans bought about 16 million vehicles a year. During the recession, sales fell to 9 million and sales have recovered to 12 million and are on track to hit 14 million this year.

With cheap energy, a weak US dollar (which makes exports more competitive) and rising wages in China, American manufacturing is ''re-shoring''. Stronger vehicle sales will benefit not only American car manufacturers but foreign car makers selling into the US market as well.

Morphic's Chad Slater says US car sales are likely to start to return to normal. He was invested, until recently, in Fuji Heavy Industries, which owns Subaru, and is listed in Japan with large production and sales in the US.

Slater is looking at other investment opportunities among manufacturers bringing more of their production back to the US. He says more manufacturers will want to site their production where there is growing demand for their products, such as the US.